The present invention relates to a fixed type current detector which is wound around and fixed to the outer periphery of a conductor such as an electric cable or bus bar, and which detects the current flowing through the conductor.
FIG. 14 is a perspective view showing the general current detector 1. The current detector 1 has a core 4 with a gap 3, provided around a bus bar 2 as a measured body, and a magneto-electric conversion element 5 provided in the gap 3. The core 4 and the magneto-electric conversion element 5 are integrally molded by resins, except a portion of a window 6 of the core 4.
In the current detector 1, the core 4 is arranged such that the bus bar 2 is positioned in the window 6 of the core 4. The magnetic flux generated around the bus bar 2 by the current flowing through the bus bar 2, is converged by the core 4. The converged magnetic flux is detected by the magneto-electric conversion element 5 provided in the gap 3, and converted into an electric output. According to the converted electric output, the current flowing through the bus bar 2 is measured.
FIG. 15 is a perspective view showing a current detector 7 of the another general example, disclosed in JP-A-6-174753. The current detector 7 is provided with: a magnetic flux detector 9 wound around the bus bar 8 as a measured body; a gap 10 formed between both ends of the magnetic flux detector 9; and a magneto-electric conversion element 11 arranged in the gap 10. A display means 12 for displaying the current flowing through the measured bus bar 8, is provided. The magnetic flux detector 9 is formed by filling the conductive powder in a flexible bag body.
In the current detector 7, the magnetic flux detector 9 is wound around the bus bar 8, and the magnetic flux generated around the bus bar 8 by the current flowing through the bus bar 8, is converged by the magnetic flux detector 9. The converged magnetic flux is detected by the magneto-electric conversion element 11 provided in the gap 10, and converted into an electric output. According to the converted electric output, the display means 12 displays the current flowing through the bus bar 8.
The current detector 7 can cope with the shape of the bus bar 8, because the shape of the magnetic flux detector 9 can be freely changed.
However, in the current detector 1 shown in FIG. 14, when a current value for measurement is changed, it is necessary that the shape and dimensions of the core 4 are changed corresponding to the changed current, and it is necessary to change also the magneto-electric conversion element 5 corresponding to the change of the core 4.
Further, because the core 4 and the magneto-electric conversion element 5 are separately structured, there is a problem that the detection precision is greatly affected due to the positioning of the core 4 and the magneto-electric conversion element 5, or dimensions of the gap 3.
Further, for example, assuming that the bus bar 2 is the existing measured body and the current flowing through the bus bar 2, it is necessary that the existing bus bar 2 is disassembled, and the bus bar 2 is made to pass through the widow 6 of the core 4, and the bus bar is assembled again, therefore, the assembling operation is troublesome.
Further, in this current detector 1, in circumstances where there is a lot of vibration, such as a car, because the core 4 and the magneto-electric conversion element 5 are not fixed to the measured body 2, the magneto-electric conversion element 5 is caused to become displaced by the contact stress due to the vibration, or the impact stress due to the car accident. As a result, there is a problem that the detection accuracy is deteriorated.
Further, in the current detector 7 shown in FIG. 15, even when dimensions of the measured body 8 is any dimensions, the magnetic flux detector 9 can cope with the dimensions, because the magnetic flux detector 9 has the flexibility, as described above. However, because the magnetic flux detector 9 and the magneto-electric conversion element 11 are separately structured, there is a problem that, the detection accuracy is greatly affected due to dimensions of the gap 10 formed between both ends of the magnet flux detector 9, or positioning of the magneto-electric conversion element 11.
Further, in the current detector 7, in the same manner as the current detector 1, in the circumference having a lot of vibration such as a car, because the magnet flux detector 9 and the magneto-electric conversion element 11 are not fixed to the measured body 8, the magneto-electric conversion element 11 is caused to displacement by the contact stress due to the vibration, or the impact stress due to the car accident, thereby, there is a problem that the detection accuracy is deteriorated.
Accordingly, the object of the present invention is to provide a fixed type current detector which can cope with any type of the conductor without depending on the type of the conductor, and by which the slippage of position of the magneto-electric conversion element can be prevented.
In order to attain the above object, a fixed type current detector detecting a magnetic flux generated around a long conductor including:
a magnetic flux converging fixed member fixed around the periphery of said long conductor, said magnetic flux converging fixed member converging magnetic flux; and
a magneto-electric conversion element integrally provided with said magnetic flux converging fixed member, said magneto-electric conversion element detecting converged magnetic flux.
In the fixed type current detector, when the current flowing through the conductor is detected, the magnetic flux conversing fixed member is wound along the outer periphery of the conductor and fixed. In this state, when the current flows through the conductor, the magnetic flux generated around the conductor by the current flowing through the conductor is converged by the magnetic flux converging fixed member. The converged magnetic flux is detected by the magneto-electric conversion element integrally provided to the magnetic flux converging fixed member, and converted into the electrical output.
Because this fixed type current detector is assembled onto the conductor and fixed by winding the magnetic flux converging member along the outer periphery of the conductor and fixing it, and the magneto-electric conversion element is integrally provided onto the magnetic flux converging fixed member, thereby, an assembling and fixing operation onto the conductor becomes easy, and at the time of the assembling and fixing operation, the positional slippage of the magneto-electric conversion element does not occur. Further, the positional slippage of the magneto-electric conversion element due to the vibration stress can be prevented. As the result, the detection accuracy is increased and stabilized.
A fixed type current detector according to above structure, said magnetic flux converging fixed member includes:
a band portion wound around said periphery;
a lock portion provided on one side of said band portion, said lock portion engaging and fixing the other side of band portion;
a high permeability member integrally formed along a longitudinal direction of said band portion, said high permeability member being able to converge said magnetic flux; and
said magneto-electric conversion element integrally provided with one of said band portion and said lock portion.
This fixed type current detector fixes the band portion onto the conductor by winding the band portion around the outer periphery of the conductor, and by engaging and fixing the other end of the band portion with and to the lock portion provided on one side of the band portion. In this state, when the current flows through the conductor, the magnetic flux generated around the conductor by the current flowing through the conductor, is converged by the high permeability member which is integrally formed onto the band portion. The converged magnetic flux is detected by the magneto-electric conversion element provided on either one of the lock portion or band portion, and converted into the electric output.
In this fixed type current detector, because the band portion with which the high permeability member is integrally formed, and the lock portion which is provided on one side of the band portion and which engages with and fixes the other side of the band portion wound around the outer periphery of the conductor, are integrally formed, thereby, this fixed type current detector can cope with any type of the conductor without depending on the type of the conductor, and can be easily assembled and fixed.
Further, because the magneto-electric conversion element is integrally provided to the lock portion, and assembled and fixed onto the conductor integrally with the band portion, the magneto-electric conversion element is arranged in the closest distance to the conductor, and the positional slippage of the magneto-electric conversion element does not occur. Further, the positional slippage of the magneto-electric conversion element due to the vibration stress can be prevented. As the result, the detection accuracy is increased and stabilized.
A fixed type current detector according to above structure, said magnetic flux converging fixed member includes:
a base portion;
a surrounding portion integrally provided with said base portion, said surrounding portion fixed around said periphery;
a high permeability member integrally provided with surrounding portion, said high permeability member being able to converge said magnetic flux; and
said magneto-electric conversion element integrally provided with one of said base portion and said surrounding portion.
In this fixed type current detector, the surrounding portion is fixed onto the conductor by winding the surrounding portion around the outer periphery of the long conductor. In this state, when the current flows though the conductor, the magnetic flux generated around the conductor by the current flowing through conductor is converged by the high permeability member which is integrally formed in the surrounding portion. The converged magnetic flux is detected by the magneto-electric conversion element integrally provided on the base portion, and converted into the electrical output.
In this fixed type current detector, because the surrounding portion with which the high permeability member is integrally formed, is integrally formed with the base portion, assembling onto the conductor can be easily conducted.
Further, because the magneto-electric conversion element is integrally provided on the base portion, and is assembled and fixed onto the conductor integrally with the surrounding portion, the magneto-electric conversion element is arranged in the closest distance to the conductor, and the positional slippage of the magneto-electric conversion element does not occur. Further, the positional slippage of the magneto-electric conversion element due to the vibration stress can be prevented. As the result, the detection accuracy is increased and stabilized.
A fixed type current detector according to above structure, said high permeability member is formed by a plurality of layers.
In this fixed type current detector, because the high permeability member is formed into multi-layers, the first layer of the high permeability member arranged on the conductor side converges the magnetic flux generated around the conductor, and the second layer and subsequent layers of the high permeability member converge the magnetic flux due to the disturbance. As the result, because the influence due to the disturbance is reduced, thereby, the high accurate detection can be carried out.
A fixed type current detector according to above structure, wherein said long conductor is wound and fixed in a plurality of said fixed type current detectors, and said long conductor is formed by a plurality of electric wires.
By arranging the fixed type current detectors around a plurality of electric cables, the current flowing through the plurality of electric cables can be accurately detected.